Dental caries in Rwanda: A scoping review

Abstract Background and Aims Dental caries is an infectious disease affecting virtually all nations, including Rwanda. In Rwanda, the burden of dental caries is an issue of public health concern. To ensure the progressive eradication of the current dental caries burden in Rwanda through an evidence‐based approach, it is imperative to have an overview of the scientific research landscape of dental caries in the country. This study—a scoping review—aims to review the available evidence and gaps on dental caries in Rwanda. Methods This scoping review was reported based on the Preferred Reporting Items for systematic reviews and meta‐analyses extension for Scoping Reviews checklist. A systematic search of 11 databases was done to scoop out all literature relevant to the topic. Based on the review's selection criteria, a total of eight peer‐reviewed journal articles were included in the review. The extracted data were collated, summarized, and presented as results. Results The analysis of the data extracted from the included articles revealed a high prevalence of dental caries (ranging from 42.42% to 71.5%) in Rwanda. Also, the major pathogens causing dental caries in Rwanda as well as the impact of dental caries on the physical health and quality of life of Rwandans were identified in this review. Furthermore, the reported operative treatment options for dental caries in Rwanda were predominantly nonconservative. Also, no intervention study has been conducted on dental caries in Rwanda. Conclusion The findings in this review identify the need for massive public health interventions on dental caries in Rwanda.

Also, according to the Global Burden of Disease Study, out of 291 reported diseases and injuries, caries in permanent teeth was found to be the most common oral condition. Untreated caries in deciduous teeth and severe periodontitis in adults came in sixth and tenth place, respectively. 5 This shows that dental caries is a leading global oral condition. 6 Untreated caries affects about 3.1 billion people (44% of the world's population) worldwide. 5 Untreated caries have a significant negative impact on the quality of life of people affected by the disease; also, the management of dental caries is expensive for individuals, families, and society. 6,7 In areas with a significant socioeconomic gradient, the disease is unevenly distributed. 7 Dental caries is a condition that develops from a combination of physiological, genetic, environmental, and behavioral factors. 6 Even though dental caries is generally preventable, its frequency has barely decreased over the past 30 years, which is a severe issue. 6 In the 2013 national oral health survey in Rwanda, 64.9% of the population had experienced dental caries. 8 Based on this prevalence rate, it can be asserted that dental caries is a leading disease condition in Rwanda which requires urgent public health attention.
Scientific findings on dental caries are crucial evidence which is vital for the development of strategies, policies, laws, and interventions needed for the control of dental caries disease burden in Rwanda. 9 Although different studies had been conducted on dental caries in Rwanda; however, no known study had reviewed the available scientific evidence on dental caries in the country, to identify the emerging themes, existing evidence, and evidence gaps concerning the disease. Hence, there is an urgent need for a review of the topic area.
This study aims to do a scoping review of the empirical evidence, emerging themes, and evidence gaps in dental caries research in Rwanda. The findings obtained from this research are very important and fundamental, as they will set the pace for future research on dental caries in Rwanda.

| METHODS
This scoping review adopted the research design developed by Arksey and O'Malley, 10 and it was documented based on the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. 11 The scoping review's question was: what are the available empirical evidence and gaps on dental caries in Rwanda?
To answer the scoping review question, an all-field search of 11 electronic databases was conducted on February 09, 2023, with the aid of "OR" and "AND" Boolean operators, using these search terms: "dental caries," "tooth decay," "dental decay," "caries," and "Rwanda."  proposed that the first 100 records obtained from a Google Scholar search contain the most relevant set of literature to a search. 12,13 All retrieved literature was imported into the Rayyan web application for deduplication. 14 After deduplication, all were screened for relevance and inclusion in the scoping review. Only those literature that were peerreviewed journal articles, published in English and with accessible full texts, reporting empirical research findings on dental caries in Rwanda were considered eligible for inclusion into the scoping review. Those literatures that were nonpeer-reviewed journal articles (e.g., books, book chapters, systematic reviews, letters, opinions, comments, editorials, etc.), those that were published in a non-English language, those that did not report empirical findings on dental caries in Rwanda, those that reported empirical findings on dental caries outside Rwanda, and those that reported empirical findings on disease conditions that are not dental caries were excluded from the review.
Only those articles that were included in the review were subjected to data extraction. Data concerning the author names, publication year, study design, study objectives, study population attributes (sociodemographic features of the participants), study instruments, study results, and conclusions were obtained using a bespoke data extraction sheet adapted from previous scoping reviews. 15,16 The extracted data were thereafter collated, summarized, and presented in texts and a table. Tables A1 and A2). Figure 1 and Table 1 give a summary of the included articles.

| Sources of the included studies
All the included studies were authored by researchers affiliated to Rwanda institutions. Three studies were coauthored by researchers from Kenyan institutions, 17,20,22 one study was coauthored by a researcher from a Moroccoan institution, 17 three studies were coauthored by researchers from institutions in the United States Hackley et al. 4,8,18 and one study was coauthored by a researcher from Indian institution. 20

| Design of the included studies
All the included studies adopted a cross-sectional study design, except the study by Yadufashije et al. 17 which adopted a case-control study design. All, except two studies, 4,21 were based on primary data.

| Populations studied in Rwanda
Overall, the studies investigated a total of 3139 people in Rwanda.
Only two studies investigated child populations only, 21,22 only one study investigated adult population only, 20 and only five studies investigated a mixed population of children and adults. 4,8,[17][18][19] Also, four studies investigated dental patients, 17,18,20,22 two studies investigated households (i.e., community people), 4,8 one study investigated school children, 21 and one study investigated people (predominantly children) living with disability under the care of an NGO. 19

| Prevalence of dental caries in Rwanda
Most of the selected articles studied the prevalence of dental caries and associated risk factors. Only six studies reported the prevalence of dental caries in Rwanda. Two studies reported the prevalence rates of dental caries in children-the study by Uwayezu et al., 21 which reported a rate of 42.42% among apparently school children not living with disability, and the study by Uwayezu et al., 19

| Impact of dental caries on Rwandan population
Only three studies investigated the impact of dental caries on Rwandan population. 4,8,22 The study by Yadufashije et al. 22

| Management of dental caries in Rwanda
Only one study, by Mukashyaka et al., 18 reported the management of dental caries among a Rwandan population group. In the study, oral hygiene counseling, dental extraction, dental filling, dental cleaning, drug (antibiotic and analgesic) prescription, and/or referral to other health facilities were the treatment modalities delivered to the patients. Furthermore, denture delivery, root canal treatment, and dental crowning were not indicated among the treatment modalities.

| DISCUSSION
This scoping review indicated a high prevalence of dental caries in Rwanda due to high-risk behavior concerning dental caries. The prevalence of dental caries reported was >41% rate among the studied populations. This finding is similar to other studies in Africa concerning the prevalence of dental caries. [23][24][25][26][27] In Sudan, a prevalence of dental caries of slightly over 50% among preschool children has been reported. 24 In a meta-analysis of studies conducted on dental caries prevalence in Ethiopia, a comparatively high pooled prevalence (>40%) of dental caries was recorded. 27 Similarly, in a meta-analysis of dental caries prevalence in East Africa (including Eritrea, Sudan and Tanzania, Uganda), a pooled dental caries prevalence of 45.7% was recorded in the subregion. 26 Another systematic review and meta-synthesis of 30 studies, by Kimmie-Dhansay and Bhayat, 25 revealed discrepancies in dental caries prevalence but a relatively high incidence among 12-year-olds in Africa. The meta-synthesis reported a high prevalence in urban centers compared to rural areas, and a higher prevalence in studies conducted after 2015. The significant submission is that the burden of dental caries is increasing in Africa. However, global oral health inequalities indicate it is less prevalent in Africa compared to other continents. 28 Nevertheless, Africa carries a high rate of untreated caries due to low health infrastructure and limited access to essential oral healthcare services. 29 A study elsewhere (in the United States) showed that oral healthcare is a significant symbol of social inequality. 30 The report indicated that most people with relatively low socioeconomic status, uninsured, and minority ethnic groups have relatively low access to quality oral health care. Incidentally, people living in the lower rung of society disproportionately share common risk factors of dental caries such as high sugar consumption and poor oral hygiene.
This review also collated other dental caries determinants (apart from sugary diet intake), which include personal oral hygiene practices, gender, oral health status, and dental check-up status. Health determinants are contextual issues which explain the propensity to risk factors operating at the individual, community and global levels. 31,32 Elamin et al. 33 revealed that increased age, low maternal education, low parental involvement, low overall socioeconomic status, low frequency of tooth brushing, poor oral habits, and sugar consumption were common determinants of dental caries (see also 34,35 ).
This review revealed the common bacteria causing dental caries among Rwandan populations. In general, some oral microbes are in constant flux but serve as causative agents of dental caries. 36 Dental caries is a microbe-mediated oral disease. Chen et al. 37 explained a fourfactor theory of oral microorganisms, oral environment, host, and time responsible for dental caries. In general, sweet food consumption-a major risk factor for dental caries-was significantly associated with a decayed, missing, and filled tooth (DMFT) index. 38,39 This review also documents the pathological impact of dental caries on Rwandan populations, such as tooth pain, tooth loss, and tooth color change, among others. Dental caries also impacts the quality of life and induces negative social experiences. Ballo et al. 34 noted that dental caries significantly predicts oral health-related quality of life (OHRQoL) in preschool children. The impact is mostly negative, especially at the advanced stages of dental caries. However, the patient's age and household income are associated with the impact on quality of life. 40 Kastenbom et al. 41 showed significantly high economic costs, apart from problems relating to depression among the caries active group. Bukhari 42 also noted physiological limitations and psychological discomfort as significant impacts. Painful aching has been the most common physical discomfort. The significant impacts are many including pain, physical discomfort, psychological concerns, treatment, and social costs.
Last, this review documented the management of dental caries including dental hygiene counseling, dental extraction, dental filling, dental cleaning, and drug (antibiotic and analgesic) prescription. However, more conservative treatment options like root canal treatment and crowning were not provided in any of the reviewed studies from Rwanda. While noting the high prevalence of dental caries, with high levels of tooth loss, this review suggests a case of limited access to preventive oral healthcare in Rwanda. Hence, there is a need for massive preventive and restorative oral healthcare programs in Rwanda. The other preventive strategies include a community-based approach based on oral health education and atraumatic restorative treatments in primary health care (PHC) centers. 43

| Limitations of the review
This scoping review has its limitations. First, only eight articles met the inclusion criteria for this review despite the high prevalence of dental caries in Rwanda. This indicates a low volume of research on dental caries in Rwanda; hence, limiting the robustness of this review.
However, due to the scientific rigor of the review process, coupled with the multidisciplinary expertise of the authors (Kehinde K.
Kanmodi is a general dental practitioner and public health researcher; Peace Uwambaye is a community dentist; Jimoh Amzat is a medical sociologist; and Afeez A. Salami is an oral and maxillofacial surgery registrar) which were channeled into the review process, a very robust body of evidence was synthesized from the sparse literature.

Kehinde K. Kanmodi is an Editorial Board member of Health Science
Reports and a coauthor of this article. To minimize bias, they were excluded from all editorial decision-making related to the acceptance of this article for publication. The other authors declare no conflict of interest.

DATA AVAILABILITY STATEMENT
Data sharing is not applicable to this article as no new data were created or analyzed in this study.

TRANSPARENCY STATEMENT
The lead author Kehinde Kazeem Kanmodi affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.